Thermal induced transformations on completely Zn2+ exchanged zeolites A and Y
-
C. Weidenthaler
Abstract
The thermal stability of completely Zn2+ exchanged zeolites A and Y during calcination is studied from R.T. to 1350°C. The phase formation processes are analysed by in situ X-ray diffraction experiments as well as by quenched samples analysed and quantified by Rietveld refinements. The framework structures of the exchanged zeolites A and Y are observed to collapse above 850°C. At higher temperatures the crystallisation of Zn-β-quartz, mullite, and gahnite is initiated from the amorphous phase. Above 1050°C quartz appears and Zn-β-quartz disappears. The crystallisation of willemite is only observed for ZnA, mullite is not stable above 1150°C in both systems. Further increase in temperature leads to the crystallisation of cristobalite accompanied by the disappearance of quartz. The final crystalline components at 1350°C are, for both zeolite precursors, gahnite and cristobalite. Differences between the zeolite precursors are the amounts of amorphous phase formed, indicating a suppression of the formation of a crystalline SiO2 phase in the ZnY samples.
© 2001 Oldenbourg Wissenschaftsverlag GmbH
Articles in the same Issue
- Calculation of the elastic constants of the Al2SiO5 polymorphs andalusite, sillimanite and kyanite
- Charge density studies utilizing powder diffraction and MEM. Exploring of high Tc superconductors, C60 superconductors and manganites
- A note on mean distances, R̅[MO₆], in substituted polyhedra, [(M1-xMx′)O6], in the crystal structures of oxygen based solid solutions: local versus crystal averaging methods
- Annular dynamical disorder of the rare earth ions in a La2Zr2O7 pyrochlore via single crystal synchrotron X-ray diffraction
- Prediction of hydrogen positions in complex structures
- Thermal induced transformations on completely Zn2+ exchanged zeolites A and Y
- Molecular structure of 1-(2,4,6-tri-tert-butylphenyl)-4,4-bis(dimethylamino)-1-aza-2,3λ3-phosphabutadiene-1,3
- Crystal structure of the complex of 1,8-bis(dimethylamino)naphthalene with p-nitrosophenol by powder diffraction methods
- Crystal and molecular structure of 5-carboxy-2-thiouracil monohydrate
- Book Review
Articles in the same Issue
- Calculation of the elastic constants of the Al2SiO5 polymorphs andalusite, sillimanite and kyanite
- Charge density studies utilizing powder diffraction and MEM. Exploring of high Tc superconductors, C60 superconductors and manganites
- A note on mean distances, R̅[MO₆], in substituted polyhedra, [(M1-xMx′)O6], in the crystal structures of oxygen based solid solutions: local versus crystal averaging methods
- Annular dynamical disorder of the rare earth ions in a La2Zr2O7 pyrochlore via single crystal synchrotron X-ray diffraction
- Prediction of hydrogen positions in complex structures
- Thermal induced transformations on completely Zn2+ exchanged zeolites A and Y
- Molecular structure of 1-(2,4,6-tri-tert-butylphenyl)-4,4-bis(dimethylamino)-1-aza-2,3λ3-phosphabutadiene-1,3
- Crystal structure of the complex of 1,8-bis(dimethylamino)naphthalene with p-nitrosophenol by powder diffraction methods
- Crystal and molecular structure of 5-carboxy-2-thiouracil monohydrate
- Book Review
